Freescale Semiconductor MPC5200B Table13-38. Variable Table per Task

Programming Model
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 13-31
task’s Variable Table is desired. In addition, if a task does not use the last 16 variables, another Variable Table could start immediately after
that task’s increment values, so as to not waste memory.
When the user writes a program, or when the assembler converts the user’s programs, the SDMA engine will use the initialization variables
and constants that the user or processor should have loaded into the Variable Table. The initial index variables in the LCD tells the engine to
allocate space for the resulting variables in the loop registers. The space will be allocated consecutively, so the user knows with which register
each variable will be associated. This is important when the user’s program tries to reference one of these previously allocated variables. Also,
the eight increment variables in positions 24 through 31 of Table13-38 are preloaded by the processor, as programmed by the user.
Table13-38. Variable Table per Task
#Hex
Offset Contents Comments
0 00 Loop-Index Variable or Constant 0 These twenty-four
words (32 bits) are
used for constant
operands to the EUs,
for initialization
values, or for a place
to write results
straight to a variable
in this table. These
are typically
preloaded by the
CPU unless you are
writing directly to a
variable.
1 04 Loop-Index Variable or Constant 1
2 08 Loop-Index Variable or Constant 2
3 0c Loop-Index Variable or Constant 3
4 10 Loop-Index Variable or Constant 4
5 14 Loop-Index Variable or Constant 5
6 18 Loop-Index Variable or Constant 6
7 1c Loop-Index Variable or Constant 7
8 20 Loop-Index Variable or Constant 8
9 24 Loop-Index Variable or Constant 9
10 28 Loop-Index Variable or Constant 10
11 2c Loop-Index Variable or Constant 11
12 30 Loop-Index Variable or Constant 12
13 34 Loop-Index Variable or Constant 13
14 38 Loop-Index Variable or Constant 14
15 3c Loop-Index Variable or Constant 15
16 40 Loop-Index Variable or Constant 16
17 44 Loop-Index Variable or Constant 17
18 48 Loop-Index Variable or Constant 18
19 4c Loop-Index Variable or Constant 19
20 50 Loop-Index Variable or Constant 20
21 54 Loop-Index Variable or Constant 21
22 58 Loop-Index Variable or Constant 22
23 5c Loop-Index Variable or Constant 23
24 60 Compare Type[31:29], Reser ved[28:16], Increment Variable 0[15:0] Variables 24 - 31
may be increment
variables of the
format shown to the
left. Any of these
variables may be
used as normal
Loop-Index Variables
or Constants (like
variables 0 - 23)
instead.
25 64 Compare Type[31:29], Reser ved[28:16], Increment Variable 1[15:0]
26 68 Compare Type[31:29], Reser ved[28:16], Increment Variable 2[15:0]
27 6c Compare Type[31:29], Reserved[28:16], Increment Variable 3[15:0]
28 70 Compare Type[31:29], Reser ved[28:16], Increment Variable 4[15:0]
29 74 Compare Type[31:29], Reser ved[28:16], Increment Variable 5[15:0]
30 78 Compare Type[31:29], Reser ved[28:16], Increment Variable 6[15:0]
31 7c Compare Type[31:29], Reserved[28:16], Increment Variable 7[15:0]